A seat-belt retractor having the above features is described in EP 0 737 606 A1. If, in this type of seat-belt pretensioner, the drive connection between the pretensioner drive and belt shaft is established only by activating a coupling so that the belt shaft can rotate unobstructed in normal operation, then this condition of unobstructed rotatability of the belt shaft must also be again ensured after a coupling step has occurred so that, in the event that the seat-belt pretensioner has been equipped with a force-limiting device for example which allows controlled extraction of belt webbing, this device can operate unimpaired following the coupling step. In the known seat-belt pretensioner, a cage is detachably fastened to the housing to develop the forcibly controlled return of the coupling latch out of its load-transmitting engaged state into its release state, this cage being provided with both insertion surfaces and drive-out surfaces that respectively cooperate with trigger ramps and drive-out ramps configured on the coupling latches.
The known seat-belt pretensioner has the disadvantage that the design of the cage with different control surfaces on the one hand and the design of ramps of different fitting arrangements on the coupling latches on the other hand is complicated and costly to manufacture and assemble, so that the invention addresses the problem of simplifying the drive-out of the coupling latch after the coupling step has terminated in a seat-belt pretensioner having features of the type described above.